With the development of smart mobile terminal, the smart mobile terminal with touch function becomes popular more and more. Currently, the touch function of a display device is achieved mainly in two modes of “add on” and “on cell”. The “add on” mode indicates attaching a separate touch panel onto a display panel to form the display device having both the display function and the touch function. The “on cell” mode indicates embedding a component achieving the touch function between a color filter substrate and a polarizer provided on a back side of the color filter substrate. However, both modes need an external function module to achieve the touch function or require a post processing. Therefore, the mobile terminal having the touch function fabricated in the above two modes does not have advantages in either fabrication cost or fabrication efficiency.
Recently, another “in cell” mode is proposed, in which the touch function module is integrated onto a thin film transistor (TFT) array substrate. In this way, the integration degree of the display device having the touch function can be improved. The “in cell” mode indicates embedding the component achieving the touch function into pixels of the display device. For example, the basic principle of the “in cell” mode is as follows: a scanning line for touch (i.e., a touch scanning line) is added on the TFT array substrate, and a periodical scanning signal is applied on the touch scanning line; a touch sensing line is formed in the black matrix on a color film (CF) substrate, the touch sensing line and the above-mentioned touch scanning line are perpendicular to each other; a touch capacitor is formed on the touch scanning line on the TFT array substrate, and the scanning signal is transmitted to the touch sensing line by the touch capacitor to determine the position where touch occurs.
However, in the “in cell” mode, the touch scanning line is specially added to the TFT array and occupies a relatively large space, which is unfavorable to improve the aperture ratio. In addition, the touch sensing line is fabricated by the black matrix with conductivity. Since the black matrix is integrally formed on the CF substrate, interference or short-circuit between the touch sensing lines is unavoidable, which undoubtedly reduces the touch recognition efficiency to a large extent.